Peripheral blood mononuclear cells from pregnant and postpartum women were cultured in vitro with erythropoietin. Burst-forming unit (BFU-E)derived erythroid colonies composed of immature erythroblasts with low hemoglobin contents were observed by day 8 of culture. By day 12 of culture, numerous BFU-E-derived erythroid colonies with high hemoglobin contents were present. The Y/(y + f) globin synthetic ratio was approximately 12% in the early cultures and 6% in the late cultures, indicating that the proportion of fetal hemoglobin synthesis decreases during erythroid cell maturation. These studies also reveal that the capacity for fetal hemoglobin production by peripheral blood BFU-E in vitro is not altered during pregnancy.The major hemoglobin in humans during intrauterine life is fetal hemoglobin, a2Y2. Adult hemoglobin, a232, is first detected at around the 10th week of gestation and accounts for approximately 10% of all hemoglobins present until about the 30th week of gestation, when increasing amounts of adult hemoglobin are produced (1). By the time the infant is 6 months old, most of the hemoglobin present is adult hemoglobin (2). The mechanisms for the switching of hemoglobins during fetal development are presently not clear (3). These orderly ontogenetic changes provide an excellent model for studying gene regulation and expression. In addition, elucidation of the mechanisms for hemoglobin switching can provide a potentially useful approach to the therapy of patients with genetic disorders involving the j globin chain.Immature erythroid stem cells, burst-forming units that respond to erythropoietin (BFU-E), are present in adult human peripheral blood and can proliferate and differentiate into large colonies of erythroblasts in vitro (4, 5). These erythroblasts, derived from normal adult individuals, synthesize a substantial amount of fetal hemoglobin (6-8). Because HbF is increased in maternal peripheral blood during pregnancy (9-11), the present investigation was undertaken to determine if peripheral blood BFU-E in pregnant women have an increased capacity for HbF production in culture and to study the pattern of HbF synthesis during erythroid cell maturation in vitro. Evidence is presented that the capacity for HbF production by peripheral blood BFU-E in vitro is not altered during pregnancy. These studies also reveal that the proportion of HbF synthesis decreases during erythroid cell maturation. A preliminary report of these studies has been published elsewhere (12). METHODSSubjects. Forty-four pregnant and postpartum (3-7 months) women were studied. All women were healthy and had no known diseases or complications. Appropriate consent was obtained. [50][51][52][53][54][55][56][57][58][59][60] Ci/mmol; 1 Ci = 3.7 X 1010 becquerels), obtained from New England Nuclear, was added to each plasma clot on either day 6 or day 7, and either day 11 or day 12 of culture. Twenty-four hours later, 10 plasma clots thus labeled were pooled and washed twice with phosphate-buffered saline. Three milligrams o...
This report concerns the detection of two abnormal hemoglobins (Hb), Hb Manitoba and Hb G Coushatta, during analysis for glycohemoglobin (Hb A1c). Blood samples from two diabetic patients, analyzed for Hb A1c by HPLC, were found to contain additional Hb peaks. The presence of an abnormal Hb was confirmed in both instances by hemoglobinopathy studies. Structural studies determined the two Hb variants to be Hb Manitoba (alpha 2 102 Ser----Arg beta 2) and Hb G-Coushatta (alpha 2 beta 2 22 Glu----Ala). The significance of the presence of an abnormal Hb in Hb A1c analysis is discussed.
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